For more information, see the following topics:Instrument tracks provide the same audio signal routing options as Auxiliary Input tracks, except that their input must come from an instrument plug-in inserted on that Instrument track, or from a bus or hardware input.Instrument tracks are used as inputs for instrument plug-ins, and other sources (including internal busses). They can be fully automated. When using an Instrument track as an input for an external source, adjust the output level at the source to achieve proper recording level.